Thermodynamic study of dilute aqueous solutions of organic compounds. Part 4.—Cyclic and straight chain secondary alcohols

Abstract

Values of the enthalpy, entropy and free energy of solution and hydration are reported for cyclopentanol, cyclohexanol, cycloheptanol, butan-2-ol, pentan-3-ol, hexan-3-ol and heptan-4-ol. Aqueous solutions of cyclic alcohols are thermodynamically more stable, mainly because of entropy effects, than those of the corresponding open chain secondary alcohols. ΔH^°_h varies linearly with ΔS^°_h, but the values for cyclic and secondary aliphatic alcohols lie on different straight lines.

Parameters in the equation ΔH^°_h=α+β(ΔS^°_h+ 45) were calculated for all classes of monofunctional compounds so far investigated. The dependence of α on the type of functional group and on the type of hydrocarbon chain, open or cyclic, in which the latter is inserted is discussed.